Generally, a shell-and-tube heat exchanger-type catalytic reactor is a kind of reactor which is used to efficiently remove reaction heat. In such a reactor, a solid catalyst is filled in a plurality of reaction tubes, reaction gas is fed into the reaction tubes to cause a chemical reaction for obtaining a desired product, and a heat transfer medium is circulated through the reactor shell such that the chemical reaction can occur in the optimal state.
In the shell-and-tube catalytic reactor, hot spots tend to occur at a local point in the reaction tubes, and such hot spots cause problems, such as the deterioration of a catalyst, leading to a reduction in catalyst life, and a reduction in the selectivity to the desired product. Thus, various methods for efficiently transferring heat to the reaction tubes in the reactor to reduce hot spots have been attempted.
Korean Patent Laid-Open Publication No. 2001-0050267, for example, discloses an attempt to improve heat transfer performance by maintaining a constant flow rate of a heat transfer medium in any zone in a reactor through the use of a shell-and-tube heat exchanger, which comprises a circulator for the heat transfer medium, and doughnut-type and disc-type baffle plates, which are alternately disposed in the reactor shell. Also, circulation channels without reaction tubes are provided between a upper tube sheet and a lower tube sheet and between the peripheral portion and central portion in the cross section of the shell. Heat transfer medium can be transferred from the central portion to the peripheral portion or from the peripheral portion to the central portion through circulation channels in a shorter time than through the reaction tube region. Accordingly, the heat transfer medium passing through the circulation channel recovers only a small amount of reaction heat because of less frequent contact with the reaction tubes, such that it can reach the peripheral portion or the central portion at a relatively low temperature in a relatively short time, and thus can handle the reaction tubes in these portions with a relatively fresh condition of heat transfer medium.